Common eider

{{Short description|Species of bird}} {{Speciesbox | name = Common eider | image = Пухівка на Кінбурнській косі.jpg | image_caption = Adult male, breeding plumage | image2 = Common eider female at Jones Beach (04713).jpg | image2_caption = Female | status = NT | status_system = IUCN3.1 | status_ref = <ref name="iucn status 12 November 2021">{{cite iucn |author=BirdLife International |date=2018 |title=''Somateria mollissima'' |volume=2018 |article-number=e.T22680405A132525971 |doi=10.2305/IUCN.UK.2018-2.RLTS.T22680405A132525971.en |access-date=12 November 2021}}</ref> | genus = Somateria | species = mollissima | authority = (Linnaeus, 1758) | subdivision_ranks = Subspecies | subdivision = * ''S. m. mollissima'' (Linnaeus, 1758) * ''S. m. faeroeensis'' C. L. Brehm, 1831 * ''S. m. v-nigra'' Bonaparte and G. R. Gray, 1855 * ''S. m. borealis'' (C. L. Brehm, 1824) * ''S. m. sedentaria'' Snyder, 1941 * ''S. m. dresseri'' Sharpe, 187FF99551 | range_map = Somateria mollissima map.svg | range_map_caption = Range of ''S. mollissima'' {{leftlegend|#FF9955|Breeding range|outline=gray}}{{leftlegend|#87AADE|Wintering/Feeding range|outline=gray}} | synonyms = ''Anas mollissima'' {{small|Linnaeus, 1758}} }} right|thumb|Common eiders in the breeding season on Texel, the Netherlands

The '''common eider''' (pronounced {{IPAc-en|'|ai|.|d|@r}}) ('''''Somateria mollissima'''''), also called '''St. Cuthbert's duck''' or '''Cuddy's duck''', is a large ({{cvt|50|–|71|cm}} in body length) sea-duck that is distributed over the northern coasts of Europe, North America and eastern Siberia. It breeds in Arctic and some northern temperate regions, but winters somewhat farther south in temperate zones, when it can form large flocks on coastal waters. It can fly at speeds up to {{cvt|113|km/h}}.<ref name=birds-speed/>

The eider's nest is built close to the sea and is lined with eiderdown, plucked from the female's breast. This soft and warm lining has long been harvested for filling pillows and quilts, but in more recent years has been largely replaced by down from domestic farm-geese and synthetic alternatives. Although eiderdown pillows or quilts are now a rarity, typically being marketed as luxury goods, eiderdown harvesting continues and is sustainable, as it can be done after the ducklings leave the nest with no harm to the birds.

==Taxonomy== The common eider was formally named by the Swedish naturalist Carl Linnaeus in 1758 in the tenth edition of his ''Systema Naturae''. He placed it with all the other ducks in the genus ''Anas'' and coined the binomial name ''Anas mollissima''.<ref>{{cite book | last=Linnaeus | first=Carl | author-link=Carl Linnaeus | year=1758 | title= Systema Naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis | volume=1 | edition=10th | page=124 | publisher=Laurentii Salvii | location=Holmiae (Stockholm) | language=Latin | url=https://www.biodiversitylibrary.org/page/727029}}</ref> It is now placed with two other species in the genus ''Somateria'' that was introduced in 1819 by the English zoologist William Leach.<ref>{{ cite book | last=Leach | first=William Elford | author-link=William Elford Leach | editor-last=Ross | editor-first=John | editor-link=John Ross (Royal Navy officer) | year=1819 | title=A Voyage of Discovery made under the orders of the Admiralty in her Majesty's ships Isabella and Alexander, for the purpose of exploring Baffin's Bay, and enquiring into the probability of a North-West passage | location=London | publisher=John Murray | at=Appendix II, p. 48 | url=https://archive.org/details/voyageofdiscover00ross/page/48/mode/1up }}</ref><ref name=ioc>{{cite web| editor1-last=Gill | editor1-first=Frank | editor1-link=Frank Gill (ornithologist) | editor2-last=Donsker | editor2-first=David | editor3-last=Rasmussen | editor3-first=Pamela | editor3-link=Pamela Rasmussen | date=July 2021 | title=Screamers, ducks, geese & swans | work=IOC World Bird List Version 11.2 | url=http://www.worldbirdnames.org/bow/waterfowl/ | publisher=International Ornithologists' Union | access-date=30 November 2021 }}</ref> The genus name is derived from Ancient Greek {{linktext|σῶμα}} {{Lang|grc-Latn|sōma}} 'body' (stem ''somat-'') and {{linktext|ἔριον}} {{Lang|grc-Latn|erion}} 'wool'. The specific ''mollissimus'' is Latin, meaning 'very soft'. Both parts of the name refer to its down feathers.<ref>{{cite book | last= Jobling | first= James A | year= 2010| title= The Helm Dictionary of Scientific Bird Names | url= https://archive.org/details/Helm_Dictionary_of_Scientific_Bird_Names_by_James_A._Jobling | publisher = Christopher Helm | location = London | isbn = 978-1-4081-2501-4 |page = [https://archive.org/details/Helm_Dictionary_of_Scientific_Bird_Names_by_James_A._Jobling/page/n258 258], [https://archive.org/details/Helm_Dictionary_of_Scientific_Bird_Names_by_James_A._Jobling/page/n359 359]}}</ref>

=== Subspecies === Six subspecies are recognised:<ref name=ioc/>

* ''S. m. v-nigrum'' Bonaparte & Gray, GR, 1855 – breeds in northeast Asia and Alaska; winters in the Bering Sea and the Aleutian Islands * ''S. m. borealis'' (Brehm, CL, 1824) – breeds in northeast Canada, Greenland and Iceland; winters in the north Atlantic * ''S. m. sedentaria'' Snyder, 1941 – breeds in Hudson Bay and James Bay (Canada) * ''S. m. dresseri'' Sharpe, 1871 – breeds in southeast Canada and northeast US; winters around northwest Atlantic coasts * ''S. m. faeroeensis'' Brehm, CL, 1831 – Faroe Islands, endemic * ''S. m. mollissima'' (Linnaeus, 1758) – breeds in northwest Eurasia and locally in central Europe (lakes in the Alps) and the northern Black Sea (Crimea); winters in northwest and central Europe

==Description== thumb|A common eider skull [[File:Somateria mollissima MWNH 1023.JPG|thumb|Egg, Collection Museum Wiesbaden]]

The common eider is the largest of the four eider species, measuring {{convert|50|to|71|cm|in|frac=2|abbr=on}} in length, weighs {{convert|0.81|to|3.04|kg|lboz|frac=2|abbr=on}} and spans {{convert|80|-|110|cm|in|abbr=on}} across the wings.<ref name=AAB/><ref name=Ogilvie2004/> The average weight of 22 males in the North Atlantic was {{convert|2.21|kg|lboz|frac=2|abbr=on}} while 32 females weighed an average of {{convert|1.92|kg|lboz|frac=2|abbr=on}}.<ref name=CRC/> It is distinguished by its bulky shape and large, wedge-shaped bill. The male is distinct, with its black and white plumage and green nape. The female is a brown bird, but can still be readily distinguished from all ducks, except other eider species, on the basis of size and head shape. The drake's display call is a strange almost human-like "ah-ooo", while the duck utters hoarse quacks. The species is often readily approachable.

Drakes of the European, Asian, and eastern and western North American subspecies can be distinguished by small differences in plumage and bill colour. Nominate ''S. m. mollissima'' has a yellowish-green bill, while ''S. m. dresseri'' has a greenish-grey bill, as does the slightly smaller ''S. m. faeroeensis''. The Arctic Atlantic ''S. m. borealis'' and the Arctic Pacific ''S. m. v-nigrum'' have bright orange-yellow bills.<ref name="Madge">{{cite book |last1=Madge |first1=Steve |last2=Burn |first2=Hilary |title=Wildfowl: an identification guide to the ducks, geese and swans of the world |publisher=Christopher Helm |publication-place=London |date=1988 |isbn=0-7136-3647-5 |pages=260–262}}</ref>

==Ecology== This species dives for crustaceans and molluscs, with mussels being a favoured food. The eider will eat mussels by swallowing them whole; the shells are then crushed in their gizzard and excreted. When eating a crab, the eider will remove all of its claws and legs, and then eat the body in a similar fashion.

It is abundant, with populations of about 1.5–2 million birds in both North America and Europe, and also large but unknown numbers in eastern Siberia (HBW). Some populations are small and declining, notably the isolated Crimean population in the Black Sea is declining and of conservation concern, with only around 700–1,100 pairs.<ref name="EBBA">{{cite book |title=European Breeding Bird Atlas |publisher=Lynx Edicions |publication-place=Barcelona |date=2020 |isbn=978-84-16728-38-1 |pages=122–123}}</ref>

A particularly famous colony of eiders lives on the Farne Islands in Northumberland, England. About 1,000 pairs still nest there every year. It has been claimed that these birds were the subject of one of the first-ever bird protection laws, and that the first wildlife preserve was established for them by Saint Cuthbert in the year 676, though this is not likely to be true. No mention of the hermit having any affinity with birds is found in any documents until the publication of a story about 500 years after his death.<ref name=":0">{{Cite journal|title=The Mystery of St Cuthbert's Ducks: An Adventure in Hagiography|url=https://www.jstor.org/stable/26445774|journal=Folklore|date=2016|issn=0015-587X|pages=325–343|volume=127|issue=3|first=Antone|last=Minard|jstor=26445774}}</ref> The stories told in these later works also do not involve any concerns about habitat loss or other concepts in modern nature conservation.<ref name=":0" /> Because St. Cuthbert is the patron saint of Northumberland, it was natural that the eider should be chosen as the county's emblem bird; the birds are still often called St Cuthbert's ducks or '''Cuddy's ducks''' in the area (''Cuddy'' is the familiar form of ''Cuthbert'').

In land-locked Switzerland, a small population (around five pairs) of this normally strictly marine species has colonised some of the larger lakes since 1988, enabled by the presence of large numbers of the invasive freshwater zebra mussel, which is sufficiently similar to its natural diet for eiders to breed far inland.<ref name="EBBA"/><ref>{{cite web |title=Vogelarten: Common Eider |website=Swiss Ornithological Institute |date=2026-03-11 |url=https://www.vogelwarte.ch/en/birds-of-switzerland/common-eider/ |access-date=2026-03-17}}</ref>

In Canada's Hudson Bay, important eider die-offs were observed in the 1990s by local populations due to quickly changing ice flow patterns. The Canadian Wildlife Service has spent several years gathering up-to-date information on their populations, and preliminary results seem to show a population recovery.<ref name=seaduckjv/><ref name=Henri2012/><ref name=Chaulk2012/> The common eider is the object of the 2011 documentary ''People of a Feather'',{{Citation needed|date=June 2024}} which studies the historical relationship between the Sanikiluaq community and eiders, as well as various aspects of their ecology.<ref name=peopleofafeather/>

The common eider is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies.

The clutch consists of 3 to 8 eggs, each measuring 7.55–7.84 cm (3.0–3.1 in) in length and 4.92–5.28 cm 1.9–2.1 in width. The eggs are incubated for 24–26 days.<ref>{{Cite web |title=Common Eider Life History, All About Birds, Cornell Lab of Ornithology |url=https://www.allaboutbirds.org/guide/Common_Eider/lifehistory |access-date=2026-05-30 |website=www.allaboutbirds.org |language=en}}</ref>

==Social behaviour== Eiders are colonial breeders. They nest on coastal islands in colonies ranging in size of less than 100 to upwards of 15,000 individuals.<ref name=Chapdelaine1986a/> Female eiders frequently exhibit a high degree of natal philopatry, where they return to breed on the same island where they were hatched. This can lead to a high degree of relatedness between individuals nesting on the same island, as well as the development of kin-based female social structures.<ref name=McKinnon2006/> This relatedness has likely played a role in the evolution of co-operative breeding behaviours amongst eiders. Examples of these behaviours include laying eggs in the nests of related individuals<ref name=Andersson2007/> and crèching, where female eiders team up and share the work of rearing ducklings.<ref name=Amnat/>

==Gallery== <gallery widths=250 heights=250> File:Common eider 750pix.jpg|Adult male in eclipse plumage File:Common eider juv arp 750pix.jpg|Male juvenile in first winter plumage, similar but different from eclipse plumage File:Erfugl 1764.jpg|Female File:Holzbrücke - Obersee - Somateria mollissima 2011-01-31 16-30-48 Bildgröße ändern.jpg|Common eider on Lake Zürich Obersee, Switzerland File:Flickr - Rainbirder - Eider drake (Somateria mollissima) in flight.jpg|Male in flight File:Eider-duck fur pelerine.jpg|Eider duck skin coat File:Eider nestingboxes.JPG|Traditional man-made eider nesting boxes File:Eider nest.jpg|Eider nest on the tundra in the Canadian Arctic File:EiderCreche.jpg|Small eider creche: three adult females over six ducklings at Biddeford Pool, Maine File:Common eider (Somateria mollissima) male eclipse plumage stretching composite.jpg|Stretching File:Somateria mollissima (Iceland).jpg|Common eider with ducklings swimming File:Eider Drake in Snow.png|A Drake Common Eider in the Nonesuch River, Scarborough, Maine </gallery>

==References== {{Reflist|refs= <ref name=AAB>{{Cite AllAboutBirds|Common Eider |accessdate=17 October 2011}}</ref>

<ref name=Amnat>{{cite journal |last1=Öst |first1=Markus |first2=Colin W. |last2=Clark |first3=Mikael |last3=Kilpi |first4=Ron |last4=Ydenberg |jstor=10.1086/510213 |title=Parental effort and reproductive skew in coalitions of brood-rearing female common eiders |journal=The American Naturalist |date=January 2007 |volume=169 |issue=1 |pages=73–86 |doi=10.1086/510213 |pmid=17206586|s2cid=17841634 |url=http://edepot.wur.nl/43056 |url-access=subscription }}</ref>

<ref name=Andersson2007>{{cite journal |last1=Andersson |first1=M. |first2=P. |last2=Waldeck |year=2007 |title=Host-parasite kinship in a female-philopatric bird population: evidence from relatedness trend analysis |journal=Molecular Ecology |volume=16 |issue=13 |pages=2797–2806 |pmid=17594448 |doi=10.1111/j.1365-294x.2007.03301.x|bibcode=2007MolEc..16.2797A |s2cid=5547068 }}</ref>

<ref name=birds-speed>{{cite web |url=http://www.thetravelalmanac.com/lists/birds-speed.htm |title=The World's Fastest Birds }}</ref>

<ref name=Chapdelaine1986a>{{cite book |last1=Chapdelaine |first1=G. |first2=P. |last2=Dupuis |first3=A. |last3=Reed |year=1986 |chapter=Distribution, abondance et fluctuation des populations d'eider à duvet dans l'estuaire et le golfe du Saint-Laurent |trans-chapter=Distribution, abundance and population fluctuations of the common eider in the Estuary and Gulf of St. Lawrence |language=fr |pages=6–11 |title=Eider ducks in Canada |editor-first=A. |editor-last=Reed |series=Canadian Wildlife Service Report Series |number=47 |location=Ottawa, ON |publisher=Canadian Wildlife Service}}</ref>

<ref name=Chaulk2012>{{cite journal |title=Extinction, colonization, and distribution patterns of common eider populations nesting in a naturally fragmented landscape |journal=Canadian Journal of Zoology |first1=K.G. |last1=Chaulk |first2=G.J. |last2=Robertson |first3=W.A. |last3=Montevecchi |date=November 10, 2006 |volume=84 |number=10 |pages=1402–1408 |doi=10.1139/z06-138}}</ref>

<ref name=CRC>{{cite book |title=CRC Handbook of Avian Body Masses |editor-first=John B. Jr. |editor-last=Dunning |publisher=CRC Press |year=1992 |isbn=978-0-8493-4258-5}}</ref>

<ref name=Henri2012>{{cite book |title=A Little Less Arctic |publisher=Earth and Environmental Sciences |first1=D. |last1=Henri |first2=H.G. |last2=Gilchrist |first3=E. |last3=Peacock |chapter=Understanding and Managing Wildlife in Hudson Bay Under a Changing Climate: Some Recent Contributions from Inuit and Cree Ecological Knowledge |year=2010 |pages=267–289 |doi=10.1007/978-90-481-9121-5_13 |isbn=978-90-481-9120-8}}</ref>

<ref name=McKinnon2006>{{cite journal |last1=McKinnon |first1=L. |first2=H.G. |last2=Gilchrist |first3=K.T. |last3=Scribner |year=2006 |title=Genetic evidence for kin-based female social structure in common eiders (''Somateria mollissima'') |journal=Behavioral Ecology |volume=17 |issue=4 |pages=614–621 |doi=10.1093/beheco/ark002|doi-access= }}</ref>

<ref name=Ogilvie2004>{{cite book |last1=Ogilvie |first1=Malcolm |last2=Young |first2=Steve |title=Wildfowl of the World |publisher=New Holland Publishers |year=2004 |isbn=978-1-84330-328-2}}</ref>

<ref name=peopleofafeather>{{cite web |title=People of a Feather |url=http://www.peopleofafeather.com/ |access-date=8 February 2012}}</ref>

<ref name=seaduckjv>{{cite web |title=Common Eider (Somateria mollissima) |url=http://seaduckjv.org/infoseries/coei_sppfactsheet.pdf |work=Sea Duck Information Series |publisher=Sea Duck Joint Venture |access-date=9 March 2015 |archive-url=https://web.archive.org/web/20080907090447/http://www.seaduckjv.org/infoseries/coei_sppfactsheet.pdf |archive-date=7 September 2008 }}</ref>

}} * {{Cite web |url=http://www.bionyt.dk/Groenland-debat.html |title=New Greenland Government Allows Spring Bird Hunt |archive-url=https://web.archive.org/web/20121015190057/http://www.bionyt.dk/Groenland-debat.html |archive-date=15 October 2012 }}

==External links== {{Commons category|Somateria mollissima}} {{Wikispecies|Somateria mollissima}} * [https://www.allaboutbirds.org/guide/Common_Eider Common Eider Species Account] – Cornell Lab of Ornithology * [https://web.archive.org/web/20161023214151/http://www.massaudubon.org/our-conservation-work/wildlife-research-conservation/statewide-bird-monitoring/breeding-bird-atlases/bba2/find-a-bird/(id)/264 Massachusetts Breeding Bird Atlas – Common Eider] * {{EBirdSpecies|comeid|Common Eider}} * [https://web.archive.org/web/20181002055535/http://maineseaduck.com/ Eider Duck Hunting] information and pictures. * [https://www.youtube.com/watch?v=bfcxGusc-9U YouTube video of Eider eating a crab] * [https://web.archive.org/web/20180304044050/http://www.ornithos.de/Ornithos/Feather_Collection/Somateria_mollissima/Somateria_mollissima.htm Feathers of Common Eider (Somateria molissima)] * {{BirdLife|22680405|Somateria mollissima}} * {{Avibase|name=Somateria mollissima}} * {{VIREO|Common+Eider}} * {{Xeno-canto species|Somateria|mollissima|Common eider}}

Category:Animal taxa named by Carl Linnaeus Category:Articles containing video clips Category:Birds described in 1758 Category:Holarctic birds Category:Somateria